1. Field of the Invention
Our invention relates generally to dental examination mirrors and, more specifically, to a small, highly-reflective mirror for the microscopic survey of the interior of small cavities such as the pulp region of a human tooth.
2. Discussion of the Related Art
The use of hand mirrors for dental examinations has been known for at least a century. The typical dental hand mirror known in the art employs a glass plate with a reflective coating deposited on one side together with a handle and perhaps some form of adjustable neck. Such devices are suitable for examining the interior of the mouth and the surfaces of the teeth but are usually too large for use in examining the tooth interior except that portion visible from the exterior of the tooth.
A variety of inventive means for illumination, cleaning and positioning of dental examination mirrors have been proposed over the years by practitioners in the art. For instance, in U.S. Pat. No. 1,509,041, H. T. Hyams, discloses a dental appliance which combines a source of light, an adjustable mirror, and an optical viewing apparatus for examination of the interior of the mouth. In U.S. Pat. No. 3,368,013, the inventor discloses a dental mirror that is used with a fiber optic cable or the like for illumination. Also, in U.S. Pat. No. 4,629,425, S. G. Detsch discloses a dental mirror apparatus with integral means for delivery of pressurized air, water or combination thereof to the mirror surface for cleaning. However, none of these practitioners teach or suggest a dental mirror apparatus suitable for the examination of the interior of a tooth such as is desired during endodontic procedures.
The fundamental problems presented by the typical endodontic procedure are the small size of the interior work space, the high levels of (corrosive) body fluids generated during such procedures and the requirement for some form of distortion-free optical magnification. The typical glass dental mirror is too large to permit partial insertion into the endodontic cavity. It also is not optically suitable for use with microscopic examination equipment because the glass surface is generally insufficiently flat to avoid optical distortion of a magnified image.
The size problem can be readily corrected by using a very small reflective surface. However, a glass mirror manufactured in a very small size does not resolve either of the remaining two problems In fact, very small glass reflective surfaces tend to introduce distortion under magnification and cannot be readily bonded to the mirror neck without loss of optical flatness.
The fragility and distortion problems of small glass reflectors can be overcome by substituting a polished metal surface for the glass reflector. However, the corrosive effects of the bodily fluids generated during endodontic procedures and the repeated autoclave heating imposed on dental implements will rapidly destroy the surface polish on metallic reflectors. Practitioners in the art have suggested various solutions to these problems but none of the suggestions have properly resolved all three problems simultaneously, until now.
There is a clearly felt need in the endodontic art for a hand mirror that is suitable for use in examining the interior of the tooth under magnification without significant optical distortion. Such a mirror must also be suitable for heating to autoclave temperatures without loss of optical properties. These unresolved problems and deficiencies are clearly felt in the art and are solved by our invention in the manner described below.